Bulova Black Ruthenium Plated Sterling Silver and Natural Diamond Cross EarringsBulova Black Ruthenium Plated Sterling Silver and 1 7 CTW Black Diamond Cross Earrings Pair of dangling cross earrings feature a row of black diamonds totaling 0. 142 CTTW embedded in a narrow hoop formed in the shape of Bulova's signature tuning fork logo. Black ruthenium plated sterling silver huggie style earrings sit close to the ear lobes. Ruthenium plating helps enhance durability and preserve the shine on these earrings.